The disclosed embodiments of the present invention relate to amplifying an input signal, and more particularly, to signal amplification circuits which receive/transmit signals according to an input signal.
As people around the world embrace mobile lifestyles, there is a growing demand for their mobile devices to support several different kinds of radio connections. For example, a mobile device may have multiple wireless connections (e.g., a Bluetooth connection and a WiFi connection) at the same time. If transmitters/receivers for different radio connections are implemented in a multi-radio device individually, the hardware cost and the chip size may be high. Therefore, regarding a multi-radio device, there is a need for receiving/transmitting signals according to one input. For example, if a low-noise amplifier (LNA) of the multi-radio device can be configured to commonly amplify a plurality of radio-frequency signals, the LNA shared between different radio connections, such as the Bluetooth connection and the WiFi connection, would reduce the hardware cost and the chip size of the multi-radio device. Thus, designing a signal amplification circuit which can receive/transmit signals according to one input becomes an important issue for designers in this field.